Proliferative features and first evidence of Ornithine Decarboxylase Activity in Phytomonas Jma

MARCORA S; CARRILLO C; ZADIKIAN C; ALGRANATI ID

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Bioquímica (SAIB); 2007

Sociedad Argentina de Investigaciones Bioquímicas (SAIB)

The Phytomonas genus comprises trypanosomatid flagellates infecting a wide varitey of plants. Despite Phytomonas spp. produce important economic losses and are phylogenetically close to human patogen parasites, their life cycle and biochemical features are still poorly known. In this work we have studied the in vitro growth kinetic in Phytomonas Jma promastigotes cultured in different media (LIT, BHT and SDM79). Cultures were started at 1x106cells/ml and were counted periodically. In all cases the doubling time in log phase was ~20h and the maximal cell densities were ~90x106, in all media. Phytomonas growth was not affected by the  inhibitors of polyamine biosynthesis DFMO or CHA separatelly, but was markedly reduced when both inhibitors were combined, reducing doubling time and maximal densities to 20x106cells/ml. As an initial step for the chatacterization of the polyamine metabolism in Phytomonas Jma, we measured ornithine decarboxylase (ODC) activity; it was dependent on the growth phase, being increased at log phase (from 20 to100 pmol/h/mg prot) and was inhibited by DFMO as much as Crithidia fasciculata ODC, a related trypanosomatid used as control. As these are preliminary results, further investigation on polyamine metabolism is currently underway in our lab.